Faster than wind wind powered vehicle! Violates Thermodynamics?
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Administrator • Mar 2, 2012
Member • Mar 2, 2012
I usually check CE before initiating a post. The apparent thermodynamics violation issue side tracked me.The_Big_K#-Link-Snipped-# : I had covered that vehicle long time ago. But I need to understand the question better before I can think of answers. Why should a wind powered vehicle necessarily run at speeds equal to (?!) or lower than the wind speed?
I mean, I'm not very clear how the speed of the wind (~ Kinetic Energy) is being related to the K.E. of the cart.
On the similar lines; I've always wondered the following -
Let's say like in hydro power plants; we setup a mechanism to rotate the turbine through water stream falling from height X. Then through gear train, we transfer the energy to the generator that can power a motor to pump the water back to height X.
I was told that the energy lost in the gear train & turbine would never be able to match the effort required to lift the water to height X.
Administrator • Mar 2, 2012
Member • Mar 2, 2012
I guess that the following is a stupid explanation. However, if it is true, all is explained.The_Big_KAgreed.
I'd believe the claim that the cart moves faster than wind only when I try it on my own. Of course, I don't intend to question the measurements in the above experiment but it'd still be something that just cannot be ignored.
Now as I'm writing this, if the cart is moving at speed great than the speed of the wind, then the windmill should stop as the two speeds match ( 😨 ) differential speed => zero.
Member • Mar 9, 2012
Sir, it is a trick. I agree that no generator has power greater than 100% efficiency. What if the designers are using two of them? or will the overall efficiency still be the product of inefficiencies of product of two generators?bioramaniI guess that the following is a stupid explanation. However, if it is true, all is explained.
The wind monitoring gadgets seem to be mounted on the car that is following the wind cart. Since this car is moving, it will sense a smaller wind velocity. Once the cart picks up steady state speed, it is likely that it is travelling faster than the wind velocity indicated on the pilot car.
Pretty weak explanation.
Member • Mar 9, 2012
Administrator • Mar 9, 2012
Member • Mar 9, 2012
Member • Mar 9, 2012
You cannot generate infinite electricity by connecting a generator and a motor, which is powered by the generator, which is rotated by the same motor, which is powering it. One is the energy loss due to the frictional components present in the machine. And another is the laws of physics stops it!The_Big_K#-Link-Snipped-# : I had covered that vehicle long time ago. But I need to understand the question better before I can think of answers. Why should a wind powered vehicle necessarily run at speeds equal to (?!) or lower than the wind speed?
I mean, I'm not very clear how the speed of the wind (~ Kinetic Energy) is being related to the K.E. of the cart.
Member • Mar 9, 2012
By the way, is there a way to simulate this in the labs with miniature models? I'm not sure whether the designer has made all the vehicle details available.You'll be surprised by the amount of miniaturizing-and-running that is done in generating data in Fluid Mechanics.....well, maybe not. The thing is, making scale models of things and testing them out in labs is done for any new design of any kind of fluid machinery. The people who do that are called "big boys with big toys" in the industry.
Member • Mar 9, 2012
True, but even if it is a turbine, it is hard to exceed speed of wind. Even in case of utmost efficiency, it cannot equal speed of wind.You are thinking sails, my friend. What we have here is a wind turbine. And a transmission system to transfer its power directly to the wheels. Which, as I said, has a high reduction ratio. Come to think of it, this transfer of power strategy will have a better efficiency than a sail.
I oppose your logic in post #7.I welcome your opposition. This being an internet forum for engineers, the point is not to be proven right, but to be proven wrong and hence learn something.
Because let us say, the vehicle gains a steady state and the turbine produces energy to counter drag& friction, it will only equal the speed of wind (sans any friction in parts).I am unable to follow your sequence of logic that you are using to contradict me. You are saying that the steady state is when the wind velocity on the windward face of the turbine blade drops to the point at which the vehicle has only enough power to overcome drag and friction, and hence cannot accelerate, and hence maintains velocity? That's exactly what I am saying.
Member • Mar 10, 2012
Don't get be wrong. I am not opposing you. I am unable to understand your logic. 😀GurjapI am unable to follow your sequence of logic that you are using to contradict me. You are saying that the steady state is when the wind velocity on the windward face of the turbine blade drops to the point at which the vehicle has only enough power to overcome drag and friction, and hence cannot accelerate, and hence maintains velocity? That's exactly what I am saying.
Member • Mar 10, 2012
You said that there is a wind turbine (I accept it). You said that it is powering the vehicle to certain steady state (velocity is still less that wind), I agree. Next you say once it reaches steady state, the turbine has only one work to do (to overcome drag and friction). This makes its velocity equal to that of wind.Hmmmm..... maybe I should have said it in this way: You should have a look at the blade profile. You'll see it's not a straight plank of wood. It has two faces: one face is exposed to a high-pressure wind, the other to low pressure wind. That is what causes the blade to move, as you can see.
But in no situation, can the velocity of vehicle exceed the velocity of wind. If the vehicle and turbine is 100% it will only equal the wind but never exceed the wind.
Member • Mar 10, 2012
Member • Mar 10, 2012
that is exactly what bioramani is trying to say, when he says that this vehicle violates thermodynamics.The_Big_K#-Link-Snipped-# : I had covered that vehicle long time ago. But I need to understand the question better before I can think of answers. Why should a wind powered vehicle necessarily run at speeds equal to (?!) or lower than the wind speed?
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Member • Mar 14, 2012
Here it is without any comments:Without any comments? There are over 150 comments - about half of them mine.
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By the way, is there a way to simulate this in the labs with miniature models?There sure is. That's precisely what the above link shows. It's a series of detailed build videos that will show you how to build a small working model for yourself at minimal cost. If you don't put any batteries or motors in it, you'll know it's not a hoax 😀
I'm not sure whether the designer has made all the vehicle details available.We've made all the details available in ludicrous detail. You can check out our project blog at:
Member • Mar 15, 2012
Actually, it's not a turbine - but a propeller. The wheels are in fact turning the propeller, not the other way around. In the next couple of months I hope to demonstrate the vehicle going directly upwind faster than the wind. For that task we will in fact replace the propeller blades with turbine blades.GurjapYou are thinking sails, my friend. What we have here is a wind turbine. And a transmission system to transfer its power directly to the wheels.
This being an internet forum for engineers, the point is not to be proven right, but to be proven wrong and hence learn something.That's exactly the right attitude. I originally conceived of this vehicle only as a brain-teaser. We only built it because people were clearly not prepared to accept the answer I offered.
Member • Mar 16, 2012
Actually, it's not a turbine - but a propeller. The wheels are in fact turning the propeller, not the other way around.Wait up. First off, I thought propellers....well, they propelled vehicles by using external power sources, like motors and gas turbines (like on a turboprop). And the wheels are turning the propeller? So, what's turning the wheels?
Member • Mar 16, 2012
Yup. You do have the basic idea. It's a bit like a feedback loop - and therefore sounds impossible to most folks. But it's like an audio feedback loop - unplug the amp and it quickly stops. In this case it's the wind that feeds our loop.GurjapEdit: after viewing several videos, I think I get the basic picture...
Member • Mar 31, 2012
Member • Mar 31, 2012
It's no more a perpetual motion machine than a sailboat is.hans magneAre you guys discussing the possibility of this being a perpetual machine?
Member • Apr 27, 2012